Cariology & Prevention pt. 2 Flashcards
Define dental caries
A chronic, infectious, transmissible disease that has a multifactorial etiology
What are the primary etiological factors of caries?
Micro-organisms
Host
Time
Substrate (Food)
Microbes
Have
To
Sit
What are the factors within micro-organisms in caries?
- Microbial land
- Plaque composition
- Plaque acidogenicity
- Oral hygiene
What are the factors within the host in caries?
- Tooth
- Saliva
- Immune response
What are the factors within time in caries?
- Shift in microflora = fast
- Demineralization = slow
What are the factors within substrate (food)?
- Oral clearance
- Oral hygiene
- Eating frequency
- Cariogenicity
Dental caries is caused by what?
Infectious transmissible agent (S. mutans) and many non-mutans microorganisms
Can caries be passed from mother to infant? What’s the “window of infectivity”?
Yes via saliva by 2 years old
The presence of microorganisms in the mouth
Range for the “window of infectivity”
Ranges from 19-30 months, but as early as 6 months
What lives inside the mouth?
Bacteria, virus, and fungi
What bacteria is most commonly acquired from the child’s mother?
Cariogenic streptococcal strains and gram negative
Once teeth erupt, ___ can be detected
Mutans Streptococci
What are the phases of vertical transmission of caries?
Mother, father, and other caregiver –> Mutans streptococci (MS) –> primary teeth –> permanent teeth
What are the 2 ways you can get horizontal transmission of caries?
Intimate playmates –> Mutans Streptococci (MS) –> primary teeth
Spouse or partner –> Mutans Streptococci (MS) –> permanent teeth
The window for infectivity of Mutans Streptococci (MS) Colonization ranges from ___ months but has been found as early as ___ months
19-30
6
Growth and metabolism of oral bacteria is regulated by:
Saliva (pH, temp, nutrition)
Diet (carbohydrate-rich diet)
When is dynamic balance established?
When plaque composition is stable over time despite regular environmental changes
___ results from a community that has reached microbial homeostasis
Healthy plaque
What results in disease/dental plaque?
Disruption/dysfunction of microbial homeostasis
At ___ month, there’s microbial homeostasis
1
2 healthy plaque benefits
- Prevent colonization and infection by producing acids
- Suppress over growth of pathogens (fungi)
What is the most current hypothesis of the etiology of caries?
Extended Caries Ecological Hypothesis
Specific plaque hypothesis
Only a few species are involved in the disease
Non-specific plaque hypothesis
Disease is the outcome of the overall activity of the total plaque microflora
- Everything causes disease
Ecological plaque hypothesis
Disease is caused by a shift in balance of resident microflora due to environmental conditions
- Ex: pH shift
Extended ecological plaque hypothesis
Given the right environment, even these good bacteria can cause demineralization and destruction of teeth
Describe dental biofilm
- Cream-colored mass collect on teeth and edge of gums
- Community of microorganisms adhere to each other and attach to a surface
- Non-shedding teeth allow more time for development of layers of bacteria
If dental plaque is left undisturbed, biofilm rapidly builds up to sufficient depth to produce an ___ environment
Anaerobic
Do teeth or gums allow more bacteria to grow?
Teeth b/c they’re non-shedding
What are the 5 stages of development in dental plaque? How soon do these stages appear?
Pellicle formation (min)
Attachment of a single bacteria (0-24 hr)
Growth of microcolonies (4-24 hr)
Succession (diversity) (1-7 days)
Climax community (mature biofilm) (1 week+)
Describe Pellicle
Acellular proteinaceous film that forms on tooth surface within minutes of eruption or cleaning
- Instantly acquired from saliva
- 1st stage in dental plauqe development
What does pellicle consist of?
- Salivary glycoproteins
- Phosphoproteins
- Lipids
- Components of gingival crevicular fluid
- Dead bacteria
NO LIVING BACTERIA
Pellicle has ___ permeability that restricts transport of ions in and out of dental hard tissue
Selective
Pellicle is protective as it ___ diffusion of acids, chelating agents, calcium, and phosphate ions
Slows
+ve
Pellicle enables ___ of ___ in the early stages of biofilm formation
Attachment and colonization of microbial species
-ve
It’s the rug where bacteria attaches to tooth surface
What are the key stages of biofilm formation?
- Attachment and colonization
- Growth and proliferation
- Maturation and detachment
Microorganisms become a component of biofilm, and it experiences a shift in ___ that makes it 1,000 times ___ to antibodies, antibiotics, and antimicrobial compounds
Gene expression
More Resistant
What are the first bacteria to bind to pellicle?
Streptococcus Mitis
Streptococcus Oralis
Streptococcus Sanguinis
Actinomyces
MOS Act
Which bacterial species typically appears first in the formation of biofilm/pellicle?
Streptococcal
What bacterial species is typically present after 48 hours on the biofilm?
Streptococcus and filamentous (actinomyces)
Describe streptococcus mutans
- Large and acidogenic (produce acids)
- Cause caries
- Not early colonizer
- Aciduric & acidogenic (live in & produce acid)
- Starts caries process
Describe Lactobacilli
- Part of the climax community
- Small number
- Extremely aciduric
- not early colonizer - they’re SECONDARY
- Attracted to S mutans and S sobrinus
- Contribute to demineralization
Increased pH in the mouth would help with what?
Balance the acid
What are the 2 primary streptococci species that appear in humans?
Streptococcus mutans
Streptococcus sobrinus
- Both produce acids (acidogenic) and can live in acid (aciduric)
Describe Streptococcus Sobrinus
- Better adhesion to smooth surfaces
- Arrives after S mutans colonization
- Acidogenic & acidouric
Carries can occur without ___ but NOT without ___
Without S. sobrinus
With S. mutans
What is present during the succession stage of dental plaque?
- 2 year colonizers
- Actinomyces dominate (filamentous)
What is present during the climax community stage of dental plaque?
- Acid producing bacteria
- Ex: Gram +ve Streptococci, Gram +ve rods, Actinomyces, and Lactobacili
What are the extracellular polymers of dental plaque?
Glucan (glucosyltransferases)
Fructan (fructosyltransferase)
What is the intracellular polymer of dental plaque?
Glycogen-like (storage)
What are the 3 pathways that lead to the fermentation process (bacteria + sucrose) in dental plaque?
Extracellular polymer
Intracellular polymer
lactic acid + other acids + energy
Rate and amount of acid formation ___ with age of the biofilm
Increases
Dental biofilm must be up to ___ days old before demineralization happens
2 days
- Takes 2 days to produce plaque
Acidogenic bacteria converts ___ to ___ that helps form the sticky biofilm matrix
Sucrose
Dextranpolysacchrie
Dental plaque that’s less than 12 hours old. Saliva can repair in __
10 min
Dental plaque that’s older than 48 hours. Saliva can repair in ___
4 Hours
___ is associated with root caries
Actinomyces
___ is associated with progression of caries
Lactobacilli
What are examples of initiators of caries?
S. mutans and S. sobrinus
Which of the following bacteria increase pH by generating alkali?
a. S. mitis
b. S. oralis
c. Actinomyces spp
d. Actinomyces naeslundii
Actinomyces naeslundii
Early colonizer of pre-dentate biofilm and tooth structure by binding to the pellicle first
S. Oralis, S. mitis, S. sanguinis, Actinomyces
What is not true of the acquired pellicle?
a. 1 micron thick
b. Acellular, proteinaceous film
c. Forms 30 min after cleaning
d. Made up of glycoproteins, phosphoproteins, lipids, and components of crevicular fluid
Forms 30 min after cleaning
(it forms within minutes)
